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T O P I C R E V I E W

Robert Pearlman

NASA release

quote:NASA senior managers today unanimously recommended launching the Space Shuttle Discovery on December 7. Commander Mark Polansky and his six crewmates are scheduled to lift off at 9:35 p.m. EST on the STS-116 mission, one of the most challenging flights to continue building the International Space Station.

During the 12-day mission and three spacewalks, the crew will work closely with flight controllers at NASA's Johnson Space Center, Houston, to install a new segment of the station's girder-like truss and activate the station's permanent, complex power and cooling systems.

The launch date was announced after a traditional meeting, known as the Flight Readiness Review. During the two-day meeting, top NASA managers and engineers assess any risks associated with the mission and determine whether the shuttle's equipment, support systems and procedures are ready for flight.

"What struck me during this meeting was how complex this mission is and how it fits into the next series of assembly missions," said Associate Administrator for Space Operations Bill Gerstenmaier, who chaired the Flight Readiness Review. "We had a very good discussion on a lot of topics and our teams worked hard to make sure we had all the information we need to set our launch date for next Thursday."

Joining Commander Polansky aboard Discovery will be Pilot Bill Oefelein, mission specialists Bob Curbeam, Joan Higginbotham, Nicholas Patrick, European Space Agency astronaut Christer Fuglesang and Sunita Williams. Williams will remain aboard the station for six months. ESA astronaut Thomas Reiter, who has lived on the station since July, will return to Earth on Discovery.

Robert Pearlman

quote:Launch day has dawned at NASA's Kennedy Space Center in Florida, where Space Shuttle Discovery and a crew of seven astronauts are undergoing final preparations for the STS-116 mission to the International Space Station.

All systems onboard the space shuttle are functioning normally this morning, but there's a 60 percent chance of weather prohibiting a liftoff at 9:35 p.m. EST. A cold front moving through the area is expected to bring with it a lingering blanket of clouds and isolated light rain. The team will press on with the countdown for now, in case the weather cooperates after all.

Starting at 11:43 a.m., Discovery's orange external tank will begin loading 500,000 gallons of liquid oxygen and hydrogen. This process, called "tanking," takes about three hours to complete. The propellant levels in the tank will be continuously "topped off" until the final minutes of the countdown.

Across the space center, in the Operations and Checkout Building's crew quarters, the astronauts are scheduled to wake up just as tanking is getting under way. After breakfast, a weather briefing and suiting up, they'll board the silver Astrovan and leave for the launch pad amid the cheers of Kennedy employees.

The STS-116 mission is the 33rd for Discovery and the 117th space shuttle flight. During the 12-day mission, the crew will continue construction on the International Space Station, rewiring the orbiting laboratory and adding a segment to its integrated truss structure.

Philip

First night-time launch since Columbia?So they'll have to film the ET in other than the visible spectrum I suppose...

Robert Pearlman

quote:Originally posted by Philip:So they'll have to film the ET in other than the visible spectrum I suppose...

quote:Doing things "in the dark" has always implied either an activity meant to elude attention, or one that is performed in ignorance. So when NASA launches the space shuttle Discovery in the dark — hours after sunset — what does this imply about its intentions?

Thursday's scheduled nighttime launch marks an easing in the safety restrictions that NASA put into effect after the Columbia disaster, almost four years ago. That disaster was caused by damage to the spaceship’s thermal protection system during launch, damage caused by a falling chunk of fuel tank insulation that was actually seen as it happened — but which had consequences that were not understood until it was too late.

Since that disaster, NASA has specifically avoided launching in the dark, so that cameras monitoring the shuttle's ascent could get well-lit views of any damage done to the shuttle as it ascended. Until now. So why is this time different? It's because NASA has finally developed an array of new techniques to look for damage — and to respond if it occurs.

quote:The launch of Space Shuttle Discovery has been scrubbed due to poor weather conditions at the Kennedy Space Center in Florida.

Earlier in the day a cold front moved in over the spaceport, bringing clouds and winds into the area. The cloud ceiling proved to be too low for a safe launch, prompting NASA to postpone Discovery's flight.

Robert Pearlman

NASA managers postponed Thursday's space shuttle launch until Saturday because of low cloud cover. Friday's weather is not expected to be favorable for a launch attempt but mission managers believe conditions will improve by the weekend.

Launch of Discovery is now scheduled for 8:47 p.m. EST Dec. 9.

Friday's weather is not expected to be favorable for a launch attempt but mission managers believe conditions will improve by the weekend.

[Edited by Robert Pearlman (December 07, 2006).]

Kirsten

Kudos to NASA for thinking of us working Europeans. Now I can watch the launch live on Saturday night and sleep long on Sunday ...

Rob Joyner

With a scrub costing $500,000 each and knowing the weather will get much better in just a few days, why would NASA make an attempt on Saturday with only a 30% chance of good weather, 10% worse than was on Thursday?!

Robert Pearlman

Forecasts are not facts, they are predictions. No one can forecast exactly what the weather will be at the moment that the window opens. There have been launches in the past where the forecasts have called for as high as 90% chance of weather violating launch criteria.

Rob Joyner

It's a fact that forecasts are predictions and I've actually attended at least one of those 'iffy' launches that did launch, as well as some attempts that were scrubbed because of good weather that deteriorated just hours before launch, but forecasts are the best they have to work with.Considering the work hours and cost, it just seems more logical to wait only a couple of days, stick with a better forecast, give everyone a break over the weekend and then launch when the weather should be at least twice as good.If the weather turned bad even then, they would still have extra time in the mission launch window.Other than 'Go Fever', I don't understand why NASA wouldn't wait just a few days for predicted better weather. Anyone, am I missing something here in NASA's decision?

mjanovec

quote:Originally posted by Rob Joyner:Other than 'Go Fever', I don't understand why NASA wouldn't wait just a few days for predicted better weather. Anyone, am I missing something here in NASA's decision?

The fact they didn't launch last night pretty much rules out that "go fever" was an issue. Everything was in seemingly ideal shape, except the cloud layer at the landing facility was higher than they liked.

They simply need to schedule attempts when weather gives them a reasonable chance of success. Imagine if the weather on Saturday ends up being ideal for launch, but they had decided not to try again until next week, you can bet there would be criticism of that decision too. And the good weather next week may never materialize as predicted (note that the weather also needs to be good at the abort sites too...that's a lot of predictions that must come true), meaning that they would have given up a chance to launch on Saturday. Or a piece of equipment working well on the pad one day might start giving problems on another day. So when that ideal weather day arrives, they could be bit by a hiccup in the machinery. One could easily end up missing a launch window if one waits for near perfect conditions. As such, they need to take advantage of reasonable opportunities to launch.

$500k per scrub sounds like a lot of money, I know. I don't recall the Shuttle's current budget, but let's say it's $4 billion a year (...I believe it was $3.8 billion in 2003). One scrub is 0.0125% of the budget. Figure in 10 scrubs a year or so and that's 0.125% of the Shuttle budget...a tenth of one percent. Not much overall. And the budget, I'm sure, already has scrubs built into it. It's a fact of spaceflight.

Tom

I remember back in January 1986, NASA decided not to try a launch attempt for STS-51L, based on bad weather forecast on launch day. As it turned out, at the time of launch, weather conditions were nearly perfect. The pilot (Mike Smith) on that mission was said to be upset by the decision not to give it a shot.